01字典树

struct Trie {
  static const int N = 1e5 * 33 + 5;
  int tr[N][2];
  int cnt[N];
  int idx = 0;

  Trie() {
    idx = 0;
  }

  Trie(int n) {
    for (int i = 0; i <= n * 33; i++) {
      tr[i][0] = tr[i][1] = cnt[i] = 0;
    }
    idx = 0;
  }

  void init(int n) {
    for (int i = 0; i <= n * 33; i++) {
      tr[i][0] = tr[i][1] = cnt[i] = 0;
    }
    idx = 0;
  }

  void add(i64 x) {
    int p = 0;
    for (int i = 33; i >= 0; i--) {
      int cur = x >> i & 1;
      if (!tr[p][cur]) {
        tr[p][cur] = ++idx;
      }
      cnt[tr[p][cur]]++;
      p = tr[p][cur];
    }
  }

  void erase(i64 x) {
    int p = 0;
    for (int i = 33; i >= 0; i--) {
      int cur = x >> i & 1;
      cnt[tr[p][cur]]--;
      p = tr[p][cur];
      if (cnt[tr[p][cur]] == 0) {
        tr[p][cur] = 0;
      }
    }
  }

  i64 query(i64 x) { // min
    int p = 0;
    i64 res = 0;
    for (int i = 33; i >= 0; i--) {
      int cur = x >> i & 1;
      if (tr[p][cur] && cnt[tr[p][cur]]) {
        p = tr[p][cur];
      } else if (tr[p][cur ^ 1] && cnt[tr[p][cur ^ 1]]) {
        res |= 1ll << i;
        p = tr[p][cur ^ 1];
      } else {
        for (int j = i; j >= 0; j--) {
          res |= 1ll << j & x;
        }
        break;
      }
    }
    return res;
  }
};